Penn State scientists may have discovered way to control invasive spotted lanternfly

A pest that sparked quarantines across the region and struck terror into the hearts of fruit farmers, timber exporters, and homeowners may have met its match.

Scientists at Pennsylvania State and Cornell Universities are studying a treatment they hope will control the spotted lanternfly, the worst insect to infiltrate the United States since the gypsy moth started defoliating millions of acres of forests and killing countless trees in a process that started more than a century ago.

The research, published in the Proceedings of the Natural Academy of Sciences, involved two naturally occurring fungi – Batkoa major and Beauveria bassiana – found in soil in forests near Reading, that appeared to kill the spotted lanternfly.

The distinctive insect is an invasive plant hopper native to China, India, and Vietnam. It was first discovered in the U.S. in 2014 in Berks County, likely brought in as eggs on a crate of stones imported from China.

The bug is not a strong flier but has spread rapidly. The movement happens when females glue their inconspicuous egg masses to vehicles, outdoor furniture, or other objects.

“They are really hitting the Philadelphia area,” said Richard Roush, dean of the College of Agricultural Sciences at Penn State.

Scientists at Cornell and Penn State have been testing an EPA-approved biopesticide spray already on the market that contains B. bassiana at the Norristown Farm Park in Montgomery County in hope of containing the spread of the spotted lanternfly, he said.

The park is loaded with Tree of Heaven, one of the bug’s favorite meals. There are also plenty of maples and black walnut trees in the park, which the spotted lanternfly will feed on with their piercing-sucking mouth part, which taps into the plant like a straw to suck the sap. The residue they excrete is like a black mold that can damage the plant.

The scientists working at the Norristown site found that the spotted lanternfly nymphs move farther and faster than they expected. While a normal bug in the nymph stage may wander no more than 5 to 10 feet while it develops, the spotted lanternfly nymph moved 150 feet, said Roush.

The adults will climb up a tree, leap off and glide, then do it again, he said.

“We continue to be assaulted by invasive insects, diseases, and weeds but this one is a particularly nasty one," said Roush.

The U.S. and Pennsylvania Departments of Agriculture also are involved in the research efforts, which include studying the pest’s biology and mating behavior, as well as other control efforts.

The biopesticide used by the researchers is a water-based commercial formula that is sprayed into the trees. So far it has killed about 50% of the nymphs, said Dave Biddinger, a research professor in the department of entomology at Penn State.

“It is working better than we originally thought,” said Biddinger. “We are cautiously optimistic.”

The biggest worry is what the bugs will do to forests and industry if they are not controlled, he said.

“We are talking billions of dollars,” said Biddinger. Of particular concern are grape vines, which can die off in two years if infected by the insect, he said.

A limitation to the project is the short reach of ground spraying, especially in tall trees or dense forests.

The most effective way to treat the hard-to-reach places is aerial spraying, said Nina Jenkins, an associate research professor in the department of entomology at Penn State. In the future, that might include teams of drones flying in parallel to get good coverage, she said.

“That is emerging technology we are looking at,” Jenkins said. “That is a long way down the line.”

“Time is of the essence, and this is a pest we need to get under control,” said Jenkins, who helped develop a safe treatment for bedbugs.

Last week at the Norristown site, research technician Caryn Michel stepped over the yellow caution tape that marked one of three study areas at the 695-acre county park to examine a white tarp.

“There are some dead ones on the tarp, which is good news for us,” said Michel.

Michel and her colleagues collect the fallen leaves and dead bugs from the tarp. They examine the leaves under a microscope to see how much of the biopesticide is still present. With the bugs, they look to see if a fungus appears on the carcass, which means the treatment worked, she said.

Michel said the next step is to increase the study size, try different areas or regions, and vary the rate and quantity of the biopesticide application to see how cheaply and effectively it can control the insect.

Until then, here is little a homeowner or gardener can do other than report the sightings to the Penn State extension either online or by calling 1-888-4BADFLY, she said.

That, and kill the bugs.